One well-known method of decaffeination is disclosed in U.S. Pat. No. 2,309,092 to Berry et al. wherein caffeine is extracted from green coffee beans by contact with an aqueous extract of green coffee solubles. The caffeine-laden solution is stripped of caffeine by subsequent contact with a halogenated organic solvent such as methylene chloride. Another predominant decaffeination method involves contacting the green coffee beans directly with a halogenated organic solvent as described in U.S. Pat. No. 3,671,263 to Patel et al.
The industry has long desired to eliminate contact of such halogenated organic solvents with either the coffee beans or an extract directly contacting the coffee. Recent disclosures describe processes using caffeine adsorbents for removing the caffeine from a solution of green coffee solubles. For instance, European Pat. App. Ser. No. 79102822.8/Document No. 0,008,398 discloses using a treated activated carbon as the caffeine adsorbent. A polymeric resin caffeine adsorbent is disclosed in U.S. Pat. No. 4,031,251 to Margolis. While both types of adsorbents might be somewhat effective, they are not without certain drawbacks, such as the inability to efficiently recover the caffeine removed from the coffee extract.
Another approach to eliminating the use of halogenated organic solvents in a decaffeination process is disclosed in U.K. Pat. No. 1,516,208 wherein a liquid water-immiscible fatty material is used to recover caffeine from a vegetable extract. The solubility of caffeine in the fatty materials disclosed therein is generally low, indicating the relative inefficiency of such a process. An improvement to the process described in U.K. Pat. No. 1,516,208 is disclosed in U.K. Pat. No. 1,532,547 wherein a method of recovering caffeine from the fatty material subsequent to decaffeination of the extract is described. The improvement does not relate to the decaffeination portion of the operation.
It is an object of the present invention to provide a decaffeination process that does not involve the use of a halogenated organic solvent.
It is a further object of the present invention to provide a decaffeination process using a fatty solvent, which process is more efficient than processes heretofore disclosed by the art.